I. Field of the Invention
The present invention relates generally to the field of tree-trimming machinery and in particular it relates to series connection of a hydraulic-motor line to a plurality of hydraulic motors that rotate a plurality of staggered rotary cutter blades on cutter bars that are maneuverable universally on vehicles.
II. Description of the Prior Art
There are a wide variety of rotary saws mounted on vehicles for trimming and pruning trees. None, however, have a separate hydraulic motor for each of a plurality of rotary cutters mounted in line on a self-cleaning cutter bar in a manner taught by this invention. An example of related but different devices is is described in U.S. Pat. No. 3,246,460 granted to Patterson et al. The Patterson device taught a plurality of belt-driven rotary saws on each of a plurality of saw carriers that were pivotal. It was not an in-line series of hydraulic-powered rotary saws as described by this invention. U.S. Pat. No. 3,138,911 granted to Pounds described an in-line series of belt-driven rotary cutters on a boom mechanism that was attached to a mid section of a tractor. U.S. Pat. No. 3,1912,695 granted to Leydig et al taught staggering of a plurality of rotary cutting blades on a cutter bar with a different working relationship of parts than in this invention to prevent passage of uncut items between the rotary cutting blades. Known prior art most closely related to this invention, however, is an agricultural machine referred to as a Combined Hedger-Topper described in U.S. Pat. No. 4,067,178 granted to Miller.
Basically, the Miller patent is limited to a vehicle having a pair of two elongate booms rotatively mounted on a base member with which the two elongate booms are mounted on the vehicle. The two booms are adjustable for "heightwise" movement and for rotational orientation with respect to the ground. A plurality of power-driven saw blades are spaced apart on each of the two booms that thereby become saw booms.
Beyond these basic limitations, the Miller patent further limits itself to description of the base member as being a base portion of a U-shaped member that is attached pivotally to the vehicle for selective rotation thereabout. Then it describes hydraulic means for movement of the U-shaped member. In relation to hydraulic equipment, it then further limits itself to hydraulic means that rotate the saw blades and propel the vehicle in a combined working relationship. Finally, the Miller patent limits itself to double-end steering of the vehicle in combination with the hydraulic means that rotates the saw blades.
The instant invention is not limited to two saw booms. It can have one. It is not limited to attachment of two booms to a base member that is mounted on a vehicle. Instead, one or more cutter bars having a plurality of in-line-staggered saw blades can be attachable to conventional fasteners for lifting and maneuvering means such as scoop supports that are hydraulically operated on conventional front-end loaders and similar materials-handling equipment. The hydraulic system is not limited to use in conjunction with power transmission to wheels of a vehicle but instead, can be either independent from a vehicle hydraulic means or a takeoff from a vehicle hydraulic means that is not limited to use with power transmission to wheels of the vehicle.
Attachability to conventional equipment such as operational components of a conventional front-end loader has utility of low cost and convenience with high reliability. It eliminates need for single-purpose or highly specialized hydraulic material-handling equipment. A tractor fitted with a front-end loader can be fitted also with a tree-trimmer and pruning machine when needed intermittently or permanently. Optionally also, a tree-trimmer and pruning machine can be attached to each side of conventional equipment such as scoop fasteners for front-end-loaders to provide a two-sided tree-trimmer and pruning machine.
Further optional, different sizes of tractors and related equipment such as front-end loaders can be used for supporting and maneuvering different sizes or the same sizes of tree-trimmer and pruning machines. Some large tractors have sufficiently large-capacity hydraulic systems that they do not need separate hydraulic systems for operating hydraulic motors to rotate the rotary saw blades. However, the larger tractors may be too large for maneuverability in close-rowed trees and shrubs that need trimming and pruning. Low-cost adaptability to a wide variety of horticultural conditions and preferences is made possible by differences of this invention from the Miller device and from any other known tree trimmers and pruners.
In limiting itself to use of hydraulic means for interrelated transmission of power to wheels of a vehicle and to saw blades, the Miller patent expressed preference for use of a single hydraulic motor over a plurality of hydraulic motors for rotating a plurality of rotary saw blades on its two saw booms. This preference evidenced unfamiliarity with teachings of this invention for use of pressure-relief lines between each of a plurality of hydraulic motors and a hydraulic header. It evidenced lack of a solution to or unawareness of rotational resistance from difficult cutting conditions at one cutter blade stopping or slowing all cutter blades when ganged to a single rotational power source. In addition, it evidenced unawareness of physical as well as economic advantages to a hydraulic system for the rotary saw blades that is separate from a locomotive power source for a vehicle on which it is used.
The Miller patent's limitation to a specialized vehicle necessitated excessive vehicle length for which its double-end turning with hydraulic power became necessary to approach shorter turning radius that is inherent in conventional tractors to which the instant tree trimmer and pruner is attachable. Most tractors to which the instant invention is attachable, particularly those with a single front wheel, are equipped to turn in their own length or width by merely braking one rear wheel independently in a direction of turning. This allows them to turn between close rows of trees or even to circle a tree for round hedging or pruning when desired.
At high portions of tall trees, the hydraulic lifting means to which the instant invention is attachable is positioned towards a rear portion of the tractor to which it is attached and can turn in yet smaller circles for circle-hedging individual trees. For circle-hedging shorter trees having smaller diameters, a saw-blade cutter bar of this invention can be mounted aft of a hydraulic lifting means to position it for a shorter radius of rotation on a tractor with one rear wheel braked for a pivot point around which the remaining rear wheel rotates the tractor. The tractor then rotates in its own width which is shorter than rotating in its own length. The aft positioning of the cutter bar then turns in a smaller diameter than the width of the tractor.
Small-diameter turning of this nature is particularly important for hedge-pruning decorative trees. Christmas trees are a typical example. They can be made ideally round, tapered conically and sized for diameter and height with this invention. Other garden trees, shrubs and orchard trees can be shaped in any desired symmetrical shape and size. A small tractor with a small version of this invention can be used for custom hedging, pruning and shaping of small trees such as Christmas trees and some types of garden trees. None of this is possible with the Miller device.
All of the functions of the Miller device can be accomplished with the instant invention, however, and more. It can all be done at lower initial cost and with reliability of proven tractors that are available on the market and that are being improved constantly in ways that enhance continually their benefit for use with the instant invention.